Issue Archive

Velmex (Bloomfield, NY) offers VXM controller systems for power systems that drive motorized products including slides and rotary tables. The controller is a 2-phase, unipolar stepper motor controller that can drive and control precise movements, multi-axis, and velocity. The system is capable of controlling up to four motors, one motor at a time. Two motors can be controlled simultaneously for coordinated motion. Features include an intuitive, comprehensive command instruction set; single-chip microcontroller that digitally controls the motor phase switching and all other interface functions; elimination of noise-sensitive step and direction translation circuitry; and resonance-free motor torque from modulated current control.

John F. Kennedy Space Center, Florida
A prototype horizontal electromagnetic rail launcher has been demonstrated along with a corresponding theory. This system builds out of published work in augmented rail guns, but modifies this technology so that the motor can operate for seconds rather than milliseconds, and provide low acceleration (such as might be needed to launch an aircraft) rather than the extreme accelerations seen in the guns. The final system operates off of relatively low voltages (tens of volts), but with substantial currents. A lab bench prototype has been constructed and operated, demonstrating 13 Gs acceleration of a small 230-gram sled.

This control system concept applies principles of forced aeroelasticity to distributed electric propulsion systems.
Armstrong Flight Research Center, Edwards, California
As aeronautics engineers develop innovative distributed electric propulsion systems, they face new challenges in ensuring that these innovative aircraft are safe as well as fuel efficient. In particular, these systems involve a large number of electrically driven fan motors mounted across a wing that induce vibrations that negatively affect the aircraft’s stability. These vibrations cause problems regardless of whether the motors are bottom-mounted, top-mounted, or wing-embedded.

Goddard Space Flight Center, Greenbelt, Maryland
An efficient propulsion system would use a micropulse detonation rocket engine (–PDRE) for nano-satellite maneuverability in space. Technical objectives are to design, build, and conduct a small detonation tube experiment in order to explore the feasibility of using –PDRE for propelling a nano-satellite. The plan is to study the requirement and predict the performance of –PDRE using various candidate propellants, as well as to conduct ground experiments, demonstrate useful thrust, and measure the specific impulse in a two-year time frame, so that a follow-on project can be proposed in a future NRI Center Innovation Fund.

A low-cost glider design mitigates risk in conducting experiments for cutting-edge “green” aircraft concepts.
Armstrong Flight Research Center, Edwards, California
Researchers at NASA’s Armstrong Flight Research Center are developing a concept aircraft for testing turbo-electric distributed propulsion (TeDP) experiments. TeDP generally involves providing thrust to an aircraft via wing-mounted ducted electric fans, which consist of an electric motor, a fan, stators, and other components surrounded by cylindrical ducting within a fan case. The fan motors are powered by a combined battery and turboelectric generator system. To sufficiently power an aircraft approximately 50 ft (≈15 m) in length and with a gross weight of 25,000 lb (≈11,340 kg), this system must be capable of generating 1 MW of power.

Monitoring of complex propulsion pressure systems has been simplified with colors.
Goddard Space Flight Center, Greenbelt, Maryland
Complex pressure systems are utilized during testing in the propulsion branch as well as during the propellant loading stage of a mission. Keeping track of the state of such a system becomes more difficult as the complexity of such a system increases, and when extensive procedures are being followed. A book-keeping system is needed for visualizing these complex systems.

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